xref: /openbmc/linux/drivers/usb/gadget/legacy/inode.c (revision c7603adc)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * inode.c -- user mode filesystem api for usb gadget controllers
4  *
5  * Copyright (C) 2003-2004 David Brownell
6  * Copyright (C) 2003 Agilent Technologies
7  */
8 
9 
10 /* #define VERBOSE_DEBUG */
11 
12 #include <linux/init.h>
13 #include <linux/module.h>
14 #include <linux/fs.h>
15 #include <linux/fs_context.h>
16 #include <linux/pagemap.h>
17 #include <linux/uts.h>
18 #include <linux/wait.h>
19 #include <linux/compiler.h>
20 #include <linux/uaccess.h>
21 #include <linux/sched.h>
22 #include <linux/slab.h>
23 #include <linux/poll.h>
24 #include <linux/kthread.h>
25 #include <linux/aio.h>
26 #include <linux/uio.h>
27 #include <linux/refcount.h>
28 #include <linux/delay.h>
29 #include <linux/device.h>
30 #include <linux/moduleparam.h>
31 
32 #include <linux/usb/gadgetfs.h>
33 #include <linux/usb/gadget.h>
34 
35 
36 /*
37  * The gadgetfs API maps each endpoint to a file descriptor so that you
38  * can use standard synchronous read/write calls for I/O.  There's some
39  * O_NONBLOCK and O_ASYNC/FASYNC style i/o support.  Example usermode
40  * drivers show how this works in practice.  You can also use AIO to
41  * eliminate I/O gaps between requests, to help when streaming data.
42  *
43  * Key parts that must be USB-specific are protocols defining how the
44  * read/write operations relate to the hardware state machines.  There
45  * are two types of files.  One type is for the device, implementing ep0.
46  * The other type is for each IN or OUT endpoint.  In both cases, the
47  * user mode driver must configure the hardware before using it.
48  *
49  * - First, dev_config() is called when /dev/gadget/$CHIP is configured
50  *   (by writing configuration and device descriptors).  Afterwards it
51  *   may serve as a source of device events, used to handle all control
52  *   requests other than basic enumeration.
53  *
54  * - Then, after a SET_CONFIGURATION control request, ep_config() is
55  *   called when each /dev/gadget/ep* file is configured (by writing
56  *   endpoint descriptors).  Afterwards these files are used to write()
57  *   IN data or to read() OUT data.  To halt the endpoint, a "wrong
58  *   direction" request is issued (like reading an IN endpoint).
59  *
60  * Unlike "usbfs" the only ioctl()s are for things that are rare, and maybe
61  * not possible on all hardware.  For example, precise fault handling with
62  * respect to data left in endpoint fifos after aborted operations; or
63  * selective clearing of endpoint halts, to implement SET_INTERFACE.
64  */
65 
66 #define	DRIVER_DESC	"USB Gadget filesystem"
67 #define	DRIVER_VERSION	"24 Aug 2004"
68 
69 static const char driver_desc [] = DRIVER_DESC;
70 static const char shortname [] = "gadgetfs";
71 
72 MODULE_DESCRIPTION (DRIVER_DESC);
73 MODULE_AUTHOR ("David Brownell");
74 MODULE_LICENSE ("GPL");
75 
76 static int ep_open(struct inode *, struct file *);
77 
78 
79 /*----------------------------------------------------------------------*/
80 
81 #define GADGETFS_MAGIC		0xaee71ee7
82 
83 /* /dev/gadget/$CHIP represents ep0 and the whole device */
84 enum ep0_state {
85 	/* DISABLED is the initial state. */
86 	STATE_DEV_DISABLED = 0,
87 
88 	/* Only one open() of /dev/gadget/$CHIP; only one file tracks
89 	 * ep0/device i/o modes and binding to the controller.  Driver
90 	 * must always write descriptors to initialize the device, then
91 	 * the device becomes UNCONNECTED until enumeration.
92 	 */
93 	STATE_DEV_OPENED,
94 
95 	/* From then on, ep0 fd is in either of two basic modes:
96 	 * - (UN)CONNECTED: read usb_gadgetfs_event(s) from it
97 	 * - SETUP: read/write will transfer control data and succeed;
98 	 *   or if "wrong direction", performs protocol stall
99 	 */
100 	STATE_DEV_UNCONNECTED,
101 	STATE_DEV_CONNECTED,
102 	STATE_DEV_SETUP,
103 
104 	/* UNBOUND means the driver closed ep0, so the device won't be
105 	 * accessible again (DEV_DISABLED) until all fds are closed.
106 	 */
107 	STATE_DEV_UNBOUND,
108 };
109 
110 /* enough for the whole queue: most events invalidate others */
111 #define	N_EVENT			5
112 
113 #define RBUF_SIZE		256
114 
115 struct dev_data {
116 	spinlock_t			lock;
117 	refcount_t			count;
118 	int				udc_usage;
119 	enum ep0_state			state;		/* P: lock */
120 	struct usb_gadgetfs_event	event [N_EVENT];
121 	unsigned			ev_next;
122 	struct fasync_struct		*fasync;
123 	u8				current_config;
124 
125 	/* drivers reading ep0 MUST handle control requests (SETUP)
126 	 * reported that way; else the host will time out.
127 	 */
128 	unsigned			usermode_setup : 1,
129 					setup_in : 1,
130 					setup_can_stall : 1,
131 					setup_out_ready : 1,
132 					setup_out_error : 1,
133 					setup_abort : 1,
134 					gadget_registered : 1;
135 	unsigned			setup_wLength;
136 
137 	/* the rest is basically write-once */
138 	struct usb_config_descriptor	*config, *hs_config;
139 	struct usb_device_descriptor	*dev;
140 	struct usb_request		*req;
141 	struct usb_gadget		*gadget;
142 	struct list_head		epfiles;
143 	void				*buf;
144 	wait_queue_head_t		wait;
145 	struct super_block		*sb;
146 	struct dentry			*dentry;
147 
148 	/* except this scratch i/o buffer for ep0 */
149 	u8				rbuf[RBUF_SIZE];
150 };
151 
get_dev(struct dev_data * data)152 static inline void get_dev (struct dev_data *data)
153 {
154 	refcount_inc (&data->count);
155 }
156 
put_dev(struct dev_data * data)157 static void put_dev (struct dev_data *data)
158 {
159 	if (likely (!refcount_dec_and_test (&data->count)))
160 		return;
161 	/* needs no more cleanup */
162 	BUG_ON (waitqueue_active (&data->wait));
163 	kfree (data);
164 }
165 
dev_new(void)166 static struct dev_data *dev_new (void)
167 {
168 	struct dev_data		*dev;
169 
170 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
171 	if (!dev)
172 		return NULL;
173 	dev->state = STATE_DEV_DISABLED;
174 	refcount_set (&dev->count, 1);
175 	spin_lock_init (&dev->lock);
176 	INIT_LIST_HEAD (&dev->epfiles);
177 	init_waitqueue_head (&dev->wait);
178 	return dev;
179 }
180 
181 /*----------------------------------------------------------------------*/
182 
183 /* other /dev/gadget/$ENDPOINT files represent endpoints */
184 enum ep_state {
185 	STATE_EP_DISABLED = 0,
186 	STATE_EP_READY,
187 	STATE_EP_ENABLED,
188 	STATE_EP_UNBOUND,
189 };
190 
191 struct ep_data {
192 	struct mutex			lock;
193 	enum ep_state			state;
194 	refcount_t			count;
195 	struct dev_data			*dev;
196 	/* must hold dev->lock before accessing ep or req */
197 	struct usb_ep			*ep;
198 	struct usb_request		*req;
199 	ssize_t				status;
200 	char				name [16];
201 	struct usb_endpoint_descriptor	desc, hs_desc;
202 	struct list_head		epfiles;
203 	wait_queue_head_t		wait;
204 	struct dentry			*dentry;
205 };
206 
get_ep(struct ep_data * data)207 static inline void get_ep (struct ep_data *data)
208 {
209 	refcount_inc (&data->count);
210 }
211 
put_ep(struct ep_data * data)212 static void put_ep (struct ep_data *data)
213 {
214 	if (likely (!refcount_dec_and_test (&data->count)))
215 		return;
216 	put_dev (data->dev);
217 	/* needs no more cleanup */
218 	BUG_ON (!list_empty (&data->epfiles));
219 	BUG_ON (waitqueue_active (&data->wait));
220 	kfree (data);
221 }
222 
223 /*----------------------------------------------------------------------*/
224 
225 /* most "how to use the hardware" policy choices are in userspace:
226  * mapping endpoint roles (which the driver needs) to the capabilities
227  * which the usb controller has.  most of those capabilities are exposed
228  * implicitly, starting with the driver name and then endpoint names.
229  */
230 
231 static const char *CHIP;
232 static DEFINE_MUTEX(sb_mutex);		/* Serialize superblock operations */
233 
234 /*----------------------------------------------------------------------*/
235 
236 /* NOTE:  don't use dev_printk calls before binding to the gadget
237  * at the end of ep0 configuration, or after unbind.
238  */
239 
240 /* too wordy: dev_printk(level , &(d)->gadget->dev , fmt , ## args) */
241 #define xprintk(d,level,fmt,args...) \
242 	printk(level "%s: " fmt , shortname , ## args)
243 
244 #ifdef DEBUG
245 #define DBG(dev,fmt,args...) \
246 	xprintk(dev , KERN_DEBUG , fmt , ## args)
247 #else
248 #define DBG(dev,fmt,args...) \
249 	do { } while (0)
250 #endif /* DEBUG */
251 
252 #ifdef VERBOSE_DEBUG
253 #define VDEBUG	DBG
254 #else
255 #define VDEBUG(dev,fmt,args...) \
256 	do { } while (0)
257 #endif /* DEBUG */
258 
259 #define ERROR(dev,fmt,args...) \
260 	xprintk(dev , KERN_ERR , fmt , ## args)
261 #define INFO(dev,fmt,args...) \
262 	xprintk(dev , KERN_INFO , fmt , ## args)
263 
264 
265 /*----------------------------------------------------------------------*/
266 
267 /* SYNCHRONOUS ENDPOINT OPERATIONS (bulk/intr/iso)
268  *
269  * After opening, configure non-control endpoints.  Then use normal
270  * stream read() and write() requests; and maybe ioctl() to get more
271  * precise FIFO status when recovering from cancellation.
272  */
273 
epio_complete(struct usb_ep * ep,struct usb_request * req)274 static void epio_complete (struct usb_ep *ep, struct usb_request *req)
275 {
276 	struct ep_data	*epdata = ep->driver_data;
277 
278 	if (!req->context)
279 		return;
280 	if (req->status)
281 		epdata->status = req->status;
282 	else
283 		epdata->status = req->actual;
284 	complete ((struct completion *)req->context);
285 }
286 
287 /* tasklock endpoint, returning when it's connected.
288  * still need dev->lock to use epdata->ep.
289  */
290 static int
get_ready_ep(unsigned f_flags,struct ep_data * epdata,bool is_write)291 get_ready_ep (unsigned f_flags, struct ep_data *epdata, bool is_write)
292 {
293 	int	val;
294 
295 	if (f_flags & O_NONBLOCK) {
296 		if (!mutex_trylock(&epdata->lock))
297 			goto nonblock;
298 		if (epdata->state != STATE_EP_ENABLED &&
299 		    (!is_write || epdata->state != STATE_EP_READY)) {
300 			mutex_unlock(&epdata->lock);
301 nonblock:
302 			val = -EAGAIN;
303 		} else
304 			val = 0;
305 		return val;
306 	}
307 
308 	val = mutex_lock_interruptible(&epdata->lock);
309 	if (val < 0)
310 		return val;
311 
312 	switch (epdata->state) {
313 	case STATE_EP_ENABLED:
314 		return 0;
315 	case STATE_EP_READY:			/* not configured yet */
316 		if (is_write)
317 			return 0;
318 		fallthrough;
319 	case STATE_EP_UNBOUND:			/* clean disconnect */
320 		break;
321 	// case STATE_EP_DISABLED:		/* "can't happen" */
322 	default:				/* error! */
323 		pr_debug ("%s: ep %p not available, state %d\n",
324 				shortname, epdata, epdata->state);
325 	}
326 	mutex_unlock(&epdata->lock);
327 	return -ENODEV;
328 }
329 
330 static ssize_t
ep_io(struct ep_data * epdata,void * buf,unsigned len)331 ep_io (struct ep_data *epdata, void *buf, unsigned len)
332 {
333 	DECLARE_COMPLETION_ONSTACK (done);
334 	int value;
335 
336 	spin_lock_irq (&epdata->dev->lock);
337 	if (likely (epdata->ep != NULL)) {
338 		struct usb_request	*req = epdata->req;
339 
340 		req->context = &done;
341 		req->complete = epio_complete;
342 		req->buf = buf;
343 		req->length = len;
344 		value = usb_ep_queue (epdata->ep, req, GFP_ATOMIC);
345 	} else
346 		value = -ENODEV;
347 	spin_unlock_irq (&epdata->dev->lock);
348 
349 	if (likely (value == 0)) {
350 		value = wait_for_completion_interruptible(&done);
351 		if (value != 0) {
352 			spin_lock_irq (&epdata->dev->lock);
353 			if (likely (epdata->ep != NULL)) {
354 				DBG (epdata->dev, "%s i/o interrupted\n",
355 						epdata->name);
356 				usb_ep_dequeue (epdata->ep, epdata->req);
357 				spin_unlock_irq (&epdata->dev->lock);
358 
359 				wait_for_completion(&done);
360 				if (epdata->status == -ECONNRESET)
361 					epdata->status = -EINTR;
362 			} else {
363 				spin_unlock_irq (&epdata->dev->lock);
364 
365 				DBG (epdata->dev, "endpoint gone\n");
366 				wait_for_completion(&done);
367 				epdata->status = -ENODEV;
368 			}
369 		}
370 		return epdata->status;
371 	}
372 	return value;
373 }
374 
375 static int
ep_release(struct inode * inode,struct file * fd)376 ep_release (struct inode *inode, struct file *fd)
377 {
378 	struct ep_data		*data = fd->private_data;
379 	int value;
380 
381 	value = mutex_lock_interruptible(&data->lock);
382 	if (value < 0)
383 		return value;
384 
385 	/* clean up if this can be reopened */
386 	if (data->state != STATE_EP_UNBOUND) {
387 		data->state = STATE_EP_DISABLED;
388 		data->desc.bDescriptorType = 0;
389 		data->hs_desc.bDescriptorType = 0;
390 		usb_ep_disable(data->ep);
391 	}
392 	mutex_unlock(&data->lock);
393 	put_ep (data);
394 	return 0;
395 }
396 
ep_ioctl(struct file * fd,unsigned code,unsigned long value)397 static long ep_ioctl(struct file *fd, unsigned code, unsigned long value)
398 {
399 	struct ep_data		*data = fd->private_data;
400 	int			status;
401 
402 	if ((status = get_ready_ep (fd->f_flags, data, false)) < 0)
403 		return status;
404 
405 	spin_lock_irq (&data->dev->lock);
406 	if (likely (data->ep != NULL)) {
407 		switch (code) {
408 		case GADGETFS_FIFO_STATUS:
409 			status = usb_ep_fifo_status (data->ep);
410 			break;
411 		case GADGETFS_FIFO_FLUSH:
412 			usb_ep_fifo_flush (data->ep);
413 			break;
414 		case GADGETFS_CLEAR_HALT:
415 			status = usb_ep_clear_halt (data->ep);
416 			break;
417 		default:
418 			status = -ENOTTY;
419 		}
420 	} else
421 		status = -ENODEV;
422 	spin_unlock_irq (&data->dev->lock);
423 	mutex_unlock(&data->lock);
424 	return status;
425 }
426 
427 /*----------------------------------------------------------------------*/
428 
429 /* ASYNCHRONOUS ENDPOINT I/O OPERATIONS (bulk/intr/iso) */
430 
431 struct kiocb_priv {
432 	struct usb_request	*req;
433 	struct ep_data		*epdata;
434 	struct kiocb		*iocb;
435 	struct mm_struct	*mm;
436 	struct work_struct	work;
437 	void			*buf;
438 	struct iov_iter		to;
439 	const void		*to_free;
440 	unsigned		actual;
441 };
442 
ep_aio_cancel(struct kiocb * iocb)443 static int ep_aio_cancel(struct kiocb *iocb)
444 {
445 	struct kiocb_priv	*priv = iocb->private;
446 	struct ep_data		*epdata;
447 	int			value;
448 
449 	local_irq_disable();
450 	epdata = priv->epdata;
451 	// spin_lock(&epdata->dev->lock);
452 	if (likely(epdata && epdata->ep && priv->req))
453 		value = usb_ep_dequeue (epdata->ep, priv->req);
454 	else
455 		value = -EINVAL;
456 	// spin_unlock(&epdata->dev->lock);
457 	local_irq_enable();
458 
459 	return value;
460 }
461 
ep_user_copy_worker(struct work_struct * work)462 static void ep_user_copy_worker(struct work_struct *work)
463 {
464 	struct kiocb_priv *priv = container_of(work, struct kiocb_priv, work);
465 	struct mm_struct *mm = priv->mm;
466 	struct kiocb *iocb = priv->iocb;
467 	size_t ret;
468 
469 	kthread_use_mm(mm);
470 	ret = copy_to_iter(priv->buf, priv->actual, &priv->to);
471 	kthread_unuse_mm(mm);
472 	if (!ret)
473 		ret = -EFAULT;
474 
475 	/* completing the iocb can drop the ctx and mm, don't touch mm after */
476 	iocb->ki_complete(iocb, ret);
477 
478 	kfree(priv->buf);
479 	kfree(priv->to_free);
480 	kfree(priv);
481 }
482 
ep_aio_complete(struct usb_ep * ep,struct usb_request * req)483 static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req)
484 {
485 	struct kiocb		*iocb = req->context;
486 	struct kiocb_priv	*priv = iocb->private;
487 	struct ep_data		*epdata = priv->epdata;
488 
489 	/* lock against disconnect (and ideally, cancel) */
490 	spin_lock(&epdata->dev->lock);
491 	priv->req = NULL;
492 	priv->epdata = NULL;
493 
494 	/* if this was a write or a read returning no data then we
495 	 * don't need to copy anything to userspace, so we can
496 	 * complete the aio request immediately.
497 	 */
498 	if (priv->to_free == NULL || unlikely(req->actual == 0)) {
499 		kfree(req->buf);
500 		kfree(priv->to_free);
501 		kfree(priv);
502 		iocb->private = NULL;
503 		iocb->ki_complete(iocb,
504 				req->actual ? req->actual : (long)req->status);
505 	} else {
506 		/* ep_copy_to_user() won't report both; we hide some faults */
507 		if (unlikely(0 != req->status))
508 			DBG(epdata->dev, "%s fault %d len %d\n",
509 				ep->name, req->status, req->actual);
510 
511 		priv->buf = req->buf;
512 		priv->actual = req->actual;
513 		INIT_WORK(&priv->work, ep_user_copy_worker);
514 		schedule_work(&priv->work);
515 	}
516 
517 	usb_ep_free_request(ep, req);
518 	spin_unlock(&epdata->dev->lock);
519 	put_ep(epdata);
520 }
521 
ep_aio(struct kiocb * iocb,struct kiocb_priv * priv,struct ep_data * epdata,char * buf,size_t len)522 static ssize_t ep_aio(struct kiocb *iocb,
523 		      struct kiocb_priv *priv,
524 		      struct ep_data *epdata,
525 		      char *buf,
526 		      size_t len)
527 {
528 	struct usb_request *req;
529 	ssize_t value;
530 
531 	iocb->private = priv;
532 	priv->iocb = iocb;
533 
534 	kiocb_set_cancel_fn(iocb, ep_aio_cancel);
535 	get_ep(epdata);
536 	priv->epdata = epdata;
537 	priv->actual = 0;
538 	priv->mm = current->mm; /* mm teardown waits for iocbs in exit_aio() */
539 
540 	/* each kiocb is coupled to one usb_request, but we can't
541 	 * allocate or submit those if the host disconnected.
542 	 */
543 	spin_lock_irq(&epdata->dev->lock);
544 	value = -ENODEV;
545 	if (unlikely(epdata->ep == NULL))
546 		goto fail;
547 
548 	req = usb_ep_alloc_request(epdata->ep, GFP_ATOMIC);
549 	value = -ENOMEM;
550 	if (unlikely(!req))
551 		goto fail;
552 
553 	priv->req = req;
554 	req->buf = buf;
555 	req->length = len;
556 	req->complete = ep_aio_complete;
557 	req->context = iocb;
558 	value = usb_ep_queue(epdata->ep, req, GFP_ATOMIC);
559 	if (unlikely(0 != value)) {
560 		usb_ep_free_request(epdata->ep, req);
561 		goto fail;
562 	}
563 	spin_unlock_irq(&epdata->dev->lock);
564 	return -EIOCBQUEUED;
565 
566 fail:
567 	spin_unlock_irq(&epdata->dev->lock);
568 	kfree(priv->to_free);
569 	kfree(priv);
570 	put_ep(epdata);
571 	return value;
572 }
573 
574 static ssize_t
ep_read_iter(struct kiocb * iocb,struct iov_iter * to)575 ep_read_iter(struct kiocb *iocb, struct iov_iter *to)
576 {
577 	struct file *file = iocb->ki_filp;
578 	struct ep_data *epdata = file->private_data;
579 	size_t len = iov_iter_count(to);
580 	ssize_t value;
581 	char *buf;
582 
583 	if ((value = get_ready_ep(file->f_flags, epdata, false)) < 0)
584 		return value;
585 
586 	/* halt any endpoint by doing a "wrong direction" i/o call */
587 	if (usb_endpoint_dir_in(&epdata->desc)) {
588 		if (usb_endpoint_xfer_isoc(&epdata->desc) ||
589 		    !is_sync_kiocb(iocb)) {
590 			mutex_unlock(&epdata->lock);
591 			return -EINVAL;
592 		}
593 		DBG (epdata->dev, "%s halt\n", epdata->name);
594 		spin_lock_irq(&epdata->dev->lock);
595 		if (likely(epdata->ep != NULL))
596 			usb_ep_set_halt(epdata->ep);
597 		spin_unlock_irq(&epdata->dev->lock);
598 		mutex_unlock(&epdata->lock);
599 		return -EBADMSG;
600 	}
601 
602 	buf = kmalloc(len, GFP_KERNEL);
603 	if (unlikely(!buf)) {
604 		mutex_unlock(&epdata->lock);
605 		return -ENOMEM;
606 	}
607 	if (is_sync_kiocb(iocb)) {
608 		value = ep_io(epdata, buf, len);
609 		if (value >= 0 && (copy_to_iter(buf, value, to) != value))
610 			value = -EFAULT;
611 	} else {
612 		struct kiocb_priv *priv = kzalloc(sizeof *priv, GFP_KERNEL);
613 		value = -ENOMEM;
614 		if (!priv)
615 			goto fail;
616 		priv->to_free = dup_iter(&priv->to, to, GFP_KERNEL);
617 		if (!iter_is_ubuf(&priv->to) && !priv->to_free) {
618 			kfree(priv);
619 			goto fail;
620 		}
621 		value = ep_aio(iocb, priv, epdata, buf, len);
622 		if (value == -EIOCBQUEUED)
623 			buf = NULL;
624 	}
625 fail:
626 	kfree(buf);
627 	mutex_unlock(&epdata->lock);
628 	return value;
629 }
630 
631 static ssize_t ep_config(struct ep_data *, const char *, size_t);
632 
633 static ssize_t
ep_write_iter(struct kiocb * iocb,struct iov_iter * from)634 ep_write_iter(struct kiocb *iocb, struct iov_iter *from)
635 {
636 	struct file *file = iocb->ki_filp;
637 	struct ep_data *epdata = file->private_data;
638 	size_t len = iov_iter_count(from);
639 	bool configured;
640 	ssize_t value;
641 	char *buf;
642 
643 	if ((value = get_ready_ep(file->f_flags, epdata, true)) < 0)
644 		return value;
645 
646 	configured = epdata->state == STATE_EP_ENABLED;
647 
648 	/* halt any endpoint by doing a "wrong direction" i/o call */
649 	if (configured && !usb_endpoint_dir_in(&epdata->desc)) {
650 		if (usb_endpoint_xfer_isoc(&epdata->desc) ||
651 		    !is_sync_kiocb(iocb)) {
652 			mutex_unlock(&epdata->lock);
653 			return -EINVAL;
654 		}
655 		DBG (epdata->dev, "%s halt\n", epdata->name);
656 		spin_lock_irq(&epdata->dev->lock);
657 		if (likely(epdata->ep != NULL))
658 			usb_ep_set_halt(epdata->ep);
659 		spin_unlock_irq(&epdata->dev->lock);
660 		mutex_unlock(&epdata->lock);
661 		return -EBADMSG;
662 	}
663 
664 	buf = kmalloc(len, GFP_KERNEL);
665 	if (unlikely(!buf)) {
666 		mutex_unlock(&epdata->lock);
667 		return -ENOMEM;
668 	}
669 
670 	if (unlikely(!copy_from_iter_full(buf, len, from))) {
671 		value = -EFAULT;
672 		goto out;
673 	}
674 
675 	if (unlikely(!configured)) {
676 		value = ep_config(epdata, buf, len);
677 	} else if (is_sync_kiocb(iocb)) {
678 		value = ep_io(epdata, buf, len);
679 	} else {
680 		struct kiocb_priv *priv = kzalloc(sizeof *priv, GFP_KERNEL);
681 		value = -ENOMEM;
682 		if (priv) {
683 			value = ep_aio(iocb, priv, epdata, buf, len);
684 			if (value == -EIOCBQUEUED)
685 				buf = NULL;
686 		}
687 	}
688 out:
689 	kfree(buf);
690 	mutex_unlock(&epdata->lock);
691 	return value;
692 }
693 
694 /*----------------------------------------------------------------------*/
695 
696 /* used after endpoint configuration */
697 static const struct file_operations ep_io_operations = {
698 	.owner =	THIS_MODULE,
699 
700 	.open =		ep_open,
701 	.release =	ep_release,
702 	.llseek =	no_llseek,
703 	.unlocked_ioctl = ep_ioctl,
704 	.read_iter =	ep_read_iter,
705 	.write_iter =	ep_write_iter,
706 };
707 
708 /* ENDPOINT INITIALIZATION
709  *
710  *     fd = open ("/dev/gadget/$ENDPOINT", O_RDWR)
711  *     status = write (fd, descriptors, sizeof descriptors)
712  *
713  * That write establishes the endpoint configuration, configuring
714  * the controller to process bulk, interrupt, or isochronous transfers
715  * at the right maxpacket size, and so on.
716  *
717  * The descriptors are message type 1, identified by a host order u32
718  * at the beginning of what's written.  Descriptor order is: full/low
719  * speed descriptor, then optional high speed descriptor.
720  */
721 static ssize_t
ep_config(struct ep_data * data,const char * buf,size_t len)722 ep_config (struct ep_data *data, const char *buf, size_t len)
723 {
724 	struct usb_ep		*ep;
725 	u32			tag;
726 	int			value, length = len;
727 
728 	if (data->state != STATE_EP_READY) {
729 		value = -EL2HLT;
730 		goto fail;
731 	}
732 
733 	value = len;
734 	if (len < USB_DT_ENDPOINT_SIZE + 4)
735 		goto fail0;
736 
737 	/* we might need to change message format someday */
738 	memcpy(&tag, buf, 4);
739 	if (tag != 1) {
740 		DBG(data->dev, "config %s, bad tag %d\n", data->name, tag);
741 		goto fail0;
742 	}
743 	buf += 4;
744 	len -= 4;
745 
746 	/* NOTE:  audio endpoint extensions not accepted here;
747 	 * just don't include the extra bytes.
748 	 */
749 
750 	/* full/low speed descriptor, then high speed */
751 	memcpy(&data->desc, buf, USB_DT_ENDPOINT_SIZE);
752 	if (data->desc.bLength != USB_DT_ENDPOINT_SIZE
753 			|| data->desc.bDescriptorType != USB_DT_ENDPOINT)
754 		goto fail0;
755 	if (len != USB_DT_ENDPOINT_SIZE) {
756 		if (len != 2 * USB_DT_ENDPOINT_SIZE)
757 			goto fail0;
758 		memcpy(&data->hs_desc, buf + USB_DT_ENDPOINT_SIZE,
759 			USB_DT_ENDPOINT_SIZE);
760 		if (data->hs_desc.bLength != USB_DT_ENDPOINT_SIZE
761 				|| data->hs_desc.bDescriptorType
762 					!= USB_DT_ENDPOINT) {
763 			DBG(data->dev, "config %s, bad hs length or type\n",
764 					data->name);
765 			goto fail0;
766 		}
767 	}
768 
769 	spin_lock_irq (&data->dev->lock);
770 	if (data->dev->state == STATE_DEV_UNBOUND) {
771 		value = -ENOENT;
772 		goto gone;
773 	} else {
774 		ep = data->ep;
775 		if (ep == NULL) {
776 			value = -ENODEV;
777 			goto gone;
778 		}
779 	}
780 	switch (data->dev->gadget->speed) {
781 	case USB_SPEED_LOW:
782 	case USB_SPEED_FULL:
783 		ep->desc = &data->desc;
784 		break;
785 	case USB_SPEED_HIGH:
786 		/* fails if caller didn't provide that descriptor... */
787 		ep->desc = &data->hs_desc;
788 		break;
789 	default:
790 		DBG(data->dev, "unconnected, %s init abandoned\n",
791 				data->name);
792 		value = -EINVAL;
793 		goto gone;
794 	}
795 	value = usb_ep_enable(ep);
796 	if (value == 0) {
797 		data->state = STATE_EP_ENABLED;
798 		value = length;
799 	}
800 gone:
801 	spin_unlock_irq (&data->dev->lock);
802 	if (value < 0) {
803 fail:
804 		data->desc.bDescriptorType = 0;
805 		data->hs_desc.bDescriptorType = 0;
806 	}
807 	return value;
808 fail0:
809 	value = -EINVAL;
810 	goto fail;
811 }
812 
813 static int
ep_open(struct inode * inode,struct file * fd)814 ep_open (struct inode *inode, struct file *fd)
815 {
816 	struct ep_data		*data = inode->i_private;
817 	int			value = -EBUSY;
818 
819 	if (mutex_lock_interruptible(&data->lock) != 0)
820 		return -EINTR;
821 	spin_lock_irq (&data->dev->lock);
822 	if (data->dev->state == STATE_DEV_UNBOUND)
823 		value = -ENOENT;
824 	else if (data->state == STATE_EP_DISABLED) {
825 		value = 0;
826 		data->state = STATE_EP_READY;
827 		get_ep (data);
828 		fd->private_data = data;
829 		VDEBUG (data->dev, "%s ready\n", data->name);
830 	} else
831 		DBG (data->dev, "%s state %d\n",
832 			data->name, data->state);
833 	spin_unlock_irq (&data->dev->lock);
834 	mutex_unlock(&data->lock);
835 	return value;
836 }
837 
838 /*----------------------------------------------------------------------*/
839 
840 /* EP0 IMPLEMENTATION can be partly in userspace.
841  *
842  * Drivers that use this facility receive various events, including
843  * control requests the kernel doesn't handle.  Drivers that don't
844  * use this facility may be too simple-minded for real applications.
845  */
846 
ep0_readable(struct dev_data * dev)847 static inline void ep0_readable (struct dev_data *dev)
848 {
849 	wake_up (&dev->wait);
850 	kill_fasync (&dev->fasync, SIGIO, POLL_IN);
851 }
852 
clean_req(struct usb_ep * ep,struct usb_request * req)853 static void clean_req (struct usb_ep *ep, struct usb_request *req)
854 {
855 	struct dev_data		*dev = ep->driver_data;
856 
857 	if (req->buf != dev->rbuf) {
858 		kfree(req->buf);
859 		req->buf = dev->rbuf;
860 	}
861 	req->complete = epio_complete;
862 	dev->setup_out_ready = 0;
863 }
864 
ep0_complete(struct usb_ep * ep,struct usb_request * req)865 static void ep0_complete (struct usb_ep *ep, struct usb_request *req)
866 {
867 	struct dev_data		*dev = ep->driver_data;
868 	unsigned long		flags;
869 	int			free = 1;
870 
871 	/* for control OUT, data must still get to userspace */
872 	spin_lock_irqsave(&dev->lock, flags);
873 	if (!dev->setup_in) {
874 		dev->setup_out_error = (req->status != 0);
875 		if (!dev->setup_out_error)
876 			free = 0;
877 		dev->setup_out_ready = 1;
878 		ep0_readable (dev);
879 	}
880 
881 	/* clean up as appropriate */
882 	if (free && req->buf != &dev->rbuf)
883 		clean_req (ep, req);
884 	req->complete = epio_complete;
885 	spin_unlock_irqrestore(&dev->lock, flags);
886 }
887 
setup_req(struct usb_ep * ep,struct usb_request * req,u16 len)888 static int setup_req (struct usb_ep *ep, struct usb_request *req, u16 len)
889 {
890 	struct dev_data	*dev = ep->driver_data;
891 
892 	if (dev->setup_out_ready) {
893 		DBG (dev, "ep0 request busy!\n");
894 		return -EBUSY;
895 	}
896 	if (len > sizeof (dev->rbuf))
897 		req->buf = kmalloc(len, GFP_ATOMIC);
898 	if (req->buf == NULL) {
899 		req->buf = dev->rbuf;
900 		return -ENOMEM;
901 	}
902 	req->complete = ep0_complete;
903 	req->length = len;
904 	req->zero = 0;
905 	return 0;
906 }
907 
908 static ssize_t
ep0_read(struct file * fd,char __user * buf,size_t len,loff_t * ptr)909 ep0_read (struct file *fd, char __user *buf, size_t len, loff_t *ptr)
910 {
911 	struct dev_data			*dev = fd->private_data;
912 	ssize_t				retval;
913 	enum ep0_state			state;
914 
915 	spin_lock_irq (&dev->lock);
916 	if (dev->state <= STATE_DEV_OPENED) {
917 		retval = -EINVAL;
918 		goto done;
919 	}
920 
921 	/* report fd mode change before acting on it */
922 	if (dev->setup_abort) {
923 		dev->setup_abort = 0;
924 		retval = -EIDRM;
925 		goto done;
926 	}
927 
928 	/* control DATA stage */
929 	if ((state = dev->state) == STATE_DEV_SETUP) {
930 
931 		if (dev->setup_in) {		/* stall IN */
932 			VDEBUG(dev, "ep0in stall\n");
933 			(void) usb_ep_set_halt (dev->gadget->ep0);
934 			retval = -EL2HLT;
935 			dev->state = STATE_DEV_CONNECTED;
936 
937 		} else if (len == 0) {		/* ack SET_CONFIGURATION etc */
938 			struct usb_ep		*ep = dev->gadget->ep0;
939 			struct usb_request	*req = dev->req;
940 
941 			if ((retval = setup_req (ep, req, 0)) == 0) {
942 				++dev->udc_usage;
943 				spin_unlock_irq (&dev->lock);
944 				retval = usb_ep_queue (ep, req, GFP_KERNEL);
945 				spin_lock_irq (&dev->lock);
946 				--dev->udc_usage;
947 			}
948 			dev->state = STATE_DEV_CONNECTED;
949 
950 			/* assume that was SET_CONFIGURATION */
951 			if (dev->current_config) {
952 				unsigned power;
953 
954 				if (gadget_is_dualspeed(dev->gadget)
955 						&& (dev->gadget->speed
956 							== USB_SPEED_HIGH))
957 					power = dev->hs_config->bMaxPower;
958 				else
959 					power = dev->config->bMaxPower;
960 				usb_gadget_vbus_draw(dev->gadget, 2 * power);
961 			}
962 
963 		} else {			/* collect OUT data */
964 			if ((fd->f_flags & O_NONBLOCK) != 0
965 					&& !dev->setup_out_ready) {
966 				retval = -EAGAIN;
967 				goto done;
968 			}
969 			spin_unlock_irq (&dev->lock);
970 			retval = wait_event_interruptible (dev->wait,
971 					dev->setup_out_ready != 0);
972 
973 			/* FIXME state could change from under us */
974 			spin_lock_irq (&dev->lock);
975 			if (retval)
976 				goto done;
977 
978 			if (dev->state != STATE_DEV_SETUP) {
979 				retval = -ECANCELED;
980 				goto done;
981 			}
982 			dev->state = STATE_DEV_CONNECTED;
983 
984 			if (dev->setup_out_error)
985 				retval = -EIO;
986 			else {
987 				len = min (len, (size_t)dev->req->actual);
988 				++dev->udc_usage;
989 				spin_unlock_irq(&dev->lock);
990 				if (copy_to_user (buf, dev->req->buf, len))
991 					retval = -EFAULT;
992 				else
993 					retval = len;
994 				spin_lock_irq(&dev->lock);
995 				--dev->udc_usage;
996 				clean_req (dev->gadget->ep0, dev->req);
997 				/* NOTE userspace can't yet choose to stall */
998 			}
999 		}
1000 		goto done;
1001 	}
1002 
1003 	/* else normal: return event data */
1004 	if (len < sizeof dev->event [0]) {
1005 		retval = -EINVAL;
1006 		goto done;
1007 	}
1008 	len -= len % sizeof (struct usb_gadgetfs_event);
1009 	dev->usermode_setup = 1;
1010 
1011 scan:
1012 	/* return queued events right away */
1013 	if (dev->ev_next != 0) {
1014 		unsigned		i, n;
1015 
1016 		n = len / sizeof (struct usb_gadgetfs_event);
1017 		if (dev->ev_next < n)
1018 			n = dev->ev_next;
1019 
1020 		/* ep0 i/o has special semantics during STATE_DEV_SETUP */
1021 		for (i = 0; i < n; i++) {
1022 			if (dev->event [i].type == GADGETFS_SETUP) {
1023 				dev->state = STATE_DEV_SETUP;
1024 				n = i + 1;
1025 				break;
1026 			}
1027 		}
1028 		spin_unlock_irq (&dev->lock);
1029 		len = n * sizeof (struct usb_gadgetfs_event);
1030 		if (copy_to_user (buf, &dev->event, len))
1031 			retval = -EFAULT;
1032 		else
1033 			retval = len;
1034 		if (len > 0) {
1035 			/* NOTE this doesn't guard against broken drivers;
1036 			 * concurrent ep0 readers may lose events.
1037 			 */
1038 			spin_lock_irq (&dev->lock);
1039 			if (dev->ev_next > n) {
1040 				memmove(&dev->event[0], &dev->event[n],
1041 					sizeof (struct usb_gadgetfs_event)
1042 						* (dev->ev_next - n));
1043 			}
1044 			dev->ev_next -= n;
1045 			spin_unlock_irq (&dev->lock);
1046 		}
1047 		return retval;
1048 	}
1049 	if (fd->f_flags & O_NONBLOCK) {
1050 		retval = -EAGAIN;
1051 		goto done;
1052 	}
1053 
1054 	switch (state) {
1055 	default:
1056 		DBG (dev, "fail %s, state %d\n", __func__, state);
1057 		retval = -ESRCH;
1058 		break;
1059 	case STATE_DEV_UNCONNECTED:
1060 	case STATE_DEV_CONNECTED:
1061 		spin_unlock_irq (&dev->lock);
1062 		DBG (dev, "%s wait\n", __func__);
1063 
1064 		/* wait for events */
1065 		retval = wait_event_interruptible (dev->wait,
1066 				dev->ev_next != 0);
1067 		if (retval < 0)
1068 			return retval;
1069 		spin_lock_irq (&dev->lock);
1070 		goto scan;
1071 	}
1072 
1073 done:
1074 	spin_unlock_irq (&dev->lock);
1075 	return retval;
1076 }
1077 
1078 static struct usb_gadgetfs_event *
next_event(struct dev_data * dev,enum usb_gadgetfs_event_type type)1079 next_event (struct dev_data *dev, enum usb_gadgetfs_event_type type)
1080 {
1081 	struct usb_gadgetfs_event	*event;
1082 	unsigned			i;
1083 
1084 	switch (type) {
1085 	/* these events purge the queue */
1086 	case GADGETFS_DISCONNECT:
1087 		if (dev->state == STATE_DEV_SETUP)
1088 			dev->setup_abort = 1;
1089 		fallthrough;
1090 	case GADGETFS_CONNECT:
1091 		dev->ev_next = 0;
1092 		break;
1093 	case GADGETFS_SETUP:		/* previous request timed out */
1094 	case GADGETFS_SUSPEND:		/* same effect */
1095 		/* these events can't be repeated */
1096 		for (i = 0; i != dev->ev_next; i++) {
1097 			if (dev->event [i].type != type)
1098 				continue;
1099 			DBG(dev, "discard old event[%d] %d\n", i, type);
1100 			dev->ev_next--;
1101 			if (i == dev->ev_next)
1102 				break;
1103 			/* indices start at zero, for simplicity */
1104 			memmove (&dev->event [i], &dev->event [i + 1],
1105 				sizeof (struct usb_gadgetfs_event)
1106 					* (dev->ev_next - i));
1107 		}
1108 		break;
1109 	default:
1110 		BUG ();
1111 	}
1112 	VDEBUG(dev, "event[%d] = %d\n", dev->ev_next, type);
1113 	event = &dev->event [dev->ev_next++];
1114 	BUG_ON (dev->ev_next > N_EVENT);
1115 	memset (event, 0, sizeof *event);
1116 	event->type = type;
1117 	return event;
1118 }
1119 
1120 static ssize_t
ep0_write(struct file * fd,const char __user * buf,size_t len,loff_t * ptr)1121 ep0_write (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1122 {
1123 	struct dev_data		*dev = fd->private_data;
1124 	ssize_t			retval = -ESRCH;
1125 
1126 	/* report fd mode change before acting on it */
1127 	if (dev->setup_abort) {
1128 		dev->setup_abort = 0;
1129 		retval = -EIDRM;
1130 
1131 	/* data and/or status stage for control request */
1132 	} else if (dev->state == STATE_DEV_SETUP) {
1133 
1134 		len = min_t(size_t, len, dev->setup_wLength);
1135 		if (dev->setup_in) {
1136 			retval = setup_req (dev->gadget->ep0, dev->req, len);
1137 			if (retval == 0) {
1138 				dev->state = STATE_DEV_CONNECTED;
1139 				++dev->udc_usage;
1140 				spin_unlock_irq (&dev->lock);
1141 				if (copy_from_user (dev->req->buf, buf, len))
1142 					retval = -EFAULT;
1143 				else {
1144 					if (len < dev->setup_wLength)
1145 						dev->req->zero = 1;
1146 					retval = usb_ep_queue (
1147 						dev->gadget->ep0, dev->req,
1148 						GFP_KERNEL);
1149 				}
1150 				spin_lock_irq(&dev->lock);
1151 				--dev->udc_usage;
1152 				if (retval < 0) {
1153 					clean_req (dev->gadget->ep0, dev->req);
1154 				} else
1155 					retval = len;
1156 
1157 				return retval;
1158 			}
1159 
1160 		/* can stall some OUT transfers */
1161 		} else if (dev->setup_can_stall) {
1162 			VDEBUG(dev, "ep0out stall\n");
1163 			(void) usb_ep_set_halt (dev->gadget->ep0);
1164 			retval = -EL2HLT;
1165 			dev->state = STATE_DEV_CONNECTED;
1166 		} else {
1167 			DBG(dev, "bogus ep0out stall!\n");
1168 		}
1169 	} else
1170 		DBG (dev, "fail %s, state %d\n", __func__, dev->state);
1171 
1172 	return retval;
1173 }
1174 
1175 static int
ep0_fasync(int f,struct file * fd,int on)1176 ep0_fasync (int f, struct file *fd, int on)
1177 {
1178 	struct dev_data		*dev = fd->private_data;
1179 	// caller must F_SETOWN before signal delivery happens
1180 	VDEBUG (dev, "%s %s\n", __func__, on ? "on" : "off");
1181 	return fasync_helper (f, fd, on, &dev->fasync);
1182 }
1183 
1184 static struct usb_gadget_driver gadgetfs_driver;
1185 
1186 static int
dev_release(struct inode * inode,struct file * fd)1187 dev_release (struct inode *inode, struct file *fd)
1188 {
1189 	struct dev_data		*dev = fd->private_data;
1190 
1191 	/* closing ep0 === shutdown all */
1192 
1193 	if (dev->gadget_registered) {
1194 		usb_gadget_unregister_driver (&gadgetfs_driver);
1195 		dev->gadget_registered = false;
1196 	}
1197 
1198 	/* at this point "good" hardware has disconnected the
1199 	 * device from USB; the host won't see it any more.
1200 	 * alternatively, all host requests will time out.
1201 	 */
1202 
1203 	kfree (dev->buf);
1204 	dev->buf = NULL;
1205 
1206 	/* other endpoints were all decoupled from this device */
1207 	spin_lock_irq(&dev->lock);
1208 	dev->state = STATE_DEV_DISABLED;
1209 	spin_unlock_irq(&dev->lock);
1210 
1211 	put_dev (dev);
1212 	return 0;
1213 }
1214 
1215 static __poll_t
ep0_poll(struct file * fd,poll_table * wait)1216 ep0_poll (struct file *fd, poll_table *wait)
1217 {
1218 	struct dev_data         *dev = fd->private_data;
1219 	__poll_t                mask = 0;
1220 
1221 	if (dev->state <= STATE_DEV_OPENED)
1222 		return DEFAULT_POLLMASK;
1223 
1224 	poll_wait(fd, &dev->wait, wait);
1225 
1226 	spin_lock_irq(&dev->lock);
1227 
1228 	/* report fd mode change before acting on it */
1229 	if (dev->setup_abort) {
1230 		dev->setup_abort = 0;
1231 		mask = EPOLLHUP;
1232 		goto out;
1233 	}
1234 
1235 	if (dev->state == STATE_DEV_SETUP) {
1236 		if (dev->setup_in || dev->setup_can_stall)
1237 			mask = EPOLLOUT;
1238 	} else {
1239 		if (dev->ev_next != 0)
1240 			mask = EPOLLIN;
1241 	}
1242 out:
1243 	spin_unlock_irq(&dev->lock);
1244 	return mask;
1245 }
1246 
gadget_dev_ioctl(struct file * fd,unsigned code,unsigned long value)1247 static long gadget_dev_ioctl (struct file *fd, unsigned code, unsigned long value)
1248 {
1249 	struct dev_data		*dev = fd->private_data;
1250 	struct usb_gadget	*gadget = dev->gadget;
1251 	long ret = -ENOTTY;
1252 
1253 	spin_lock_irq(&dev->lock);
1254 	if (dev->state == STATE_DEV_OPENED ||
1255 			dev->state == STATE_DEV_UNBOUND) {
1256 		/* Not bound to a UDC */
1257 	} else if (gadget->ops->ioctl) {
1258 		++dev->udc_usage;
1259 		spin_unlock_irq(&dev->lock);
1260 
1261 		ret = gadget->ops->ioctl (gadget, code, value);
1262 
1263 		spin_lock_irq(&dev->lock);
1264 		--dev->udc_usage;
1265 	}
1266 	spin_unlock_irq(&dev->lock);
1267 
1268 	return ret;
1269 }
1270 
1271 /*----------------------------------------------------------------------*/
1272 
1273 /* The in-kernel gadget driver handles most ep0 issues, in particular
1274  * enumerating the single configuration (as provided from user space).
1275  *
1276  * Unrecognized ep0 requests may be handled in user space.
1277  */
1278 
make_qualifier(struct dev_data * dev)1279 static void make_qualifier (struct dev_data *dev)
1280 {
1281 	struct usb_qualifier_descriptor		qual;
1282 	struct usb_device_descriptor		*desc;
1283 
1284 	qual.bLength = sizeof qual;
1285 	qual.bDescriptorType = USB_DT_DEVICE_QUALIFIER;
1286 	qual.bcdUSB = cpu_to_le16 (0x0200);
1287 
1288 	desc = dev->dev;
1289 	qual.bDeviceClass = desc->bDeviceClass;
1290 	qual.bDeviceSubClass = desc->bDeviceSubClass;
1291 	qual.bDeviceProtocol = desc->bDeviceProtocol;
1292 
1293 	/* assumes ep0 uses the same value for both speeds ... */
1294 	qual.bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1295 
1296 	qual.bNumConfigurations = 1;
1297 	qual.bRESERVED = 0;
1298 
1299 	memcpy (dev->rbuf, &qual, sizeof qual);
1300 }
1301 
1302 static int
config_buf(struct dev_data * dev,u8 type,unsigned index)1303 config_buf (struct dev_data *dev, u8 type, unsigned index)
1304 {
1305 	int		len;
1306 	int		hs = 0;
1307 
1308 	/* only one configuration */
1309 	if (index > 0)
1310 		return -EINVAL;
1311 
1312 	if (gadget_is_dualspeed(dev->gadget)) {
1313 		hs = (dev->gadget->speed == USB_SPEED_HIGH);
1314 		if (type == USB_DT_OTHER_SPEED_CONFIG)
1315 			hs = !hs;
1316 	}
1317 	if (hs) {
1318 		dev->req->buf = dev->hs_config;
1319 		len = le16_to_cpu(dev->hs_config->wTotalLength);
1320 	} else {
1321 		dev->req->buf = dev->config;
1322 		len = le16_to_cpu(dev->config->wTotalLength);
1323 	}
1324 	((u8 *)dev->req->buf) [1] = type;
1325 	return len;
1326 }
1327 
1328 static int
gadgetfs_setup(struct usb_gadget * gadget,const struct usb_ctrlrequest * ctrl)1329 gadgetfs_setup (struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
1330 {
1331 	struct dev_data			*dev = get_gadget_data (gadget);
1332 	struct usb_request		*req = dev->req;
1333 	int				value = -EOPNOTSUPP;
1334 	struct usb_gadgetfs_event	*event;
1335 	u16				w_value = le16_to_cpu(ctrl->wValue);
1336 	u16				w_length = le16_to_cpu(ctrl->wLength);
1337 
1338 	if (w_length > RBUF_SIZE) {
1339 		if (ctrl->bRequestType & USB_DIR_IN) {
1340 			/* Cast away the const, we are going to overwrite on purpose. */
1341 			__le16 *temp = (__le16 *)&ctrl->wLength;
1342 
1343 			*temp = cpu_to_le16(RBUF_SIZE);
1344 			w_length = RBUF_SIZE;
1345 		} else {
1346 			return value;
1347 		}
1348 	}
1349 
1350 	spin_lock (&dev->lock);
1351 	dev->setup_abort = 0;
1352 	if (dev->state == STATE_DEV_UNCONNECTED) {
1353 		if (gadget_is_dualspeed(gadget)
1354 				&& gadget->speed == USB_SPEED_HIGH
1355 				&& dev->hs_config == NULL) {
1356 			spin_unlock(&dev->lock);
1357 			ERROR (dev, "no high speed config??\n");
1358 			return -EINVAL;
1359 		}
1360 
1361 		dev->state = STATE_DEV_CONNECTED;
1362 
1363 		INFO (dev, "connected\n");
1364 		event = next_event (dev, GADGETFS_CONNECT);
1365 		event->u.speed = gadget->speed;
1366 		ep0_readable (dev);
1367 
1368 	/* host may have given up waiting for response.  we can miss control
1369 	 * requests handled lower down (device/endpoint status and features);
1370 	 * then ep0_{read,write} will report the wrong status. controller
1371 	 * driver will have aborted pending i/o.
1372 	 */
1373 	} else if (dev->state == STATE_DEV_SETUP)
1374 		dev->setup_abort = 1;
1375 
1376 	req->buf = dev->rbuf;
1377 	req->context = NULL;
1378 	switch (ctrl->bRequest) {
1379 
1380 	case USB_REQ_GET_DESCRIPTOR:
1381 		if (ctrl->bRequestType != USB_DIR_IN)
1382 			goto unrecognized;
1383 		switch (w_value >> 8) {
1384 
1385 		case USB_DT_DEVICE:
1386 			value = min (w_length, (u16) sizeof *dev->dev);
1387 			dev->dev->bMaxPacketSize0 = dev->gadget->ep0->maxpacket;
1388 			req->buf = dev->dev;
1389 			break;
1390 		case USB_DT_DEVICE_QUALIFIER:
1391 			if (!dev->hs_config)
1392 				break;
1393 			value = min (w_length, (u16)
1394 				sizeof (struct usb_qualifier_descriptor));
1395 			make_qualifier (dev);
1396 			break;
1397 		case USB_DT_OTHER_SPEED_CONFIG:
1398 		case USB_DT_CONFIG:
1399 			value = config_buf (dev,
1400 					w_value >> 8,
1401 					w_value & 0xff);
1402 			if (value >= 0)
1403 				value = min (w_length, (u16) value);
1404 			break;
1405 		case USB_DT_STRING:
1406 			goto unrecognized;
1407 
1408 		default:		// all others are errors
1409 			break;
1410 		}
1411 		break;
1412 
1413 	/* currently one config, two speeds */
1414 	case USB_REQ_SET_CONFIGURATION:
1415 		if (ctrl->bRequestType != 0)
1416 			goto unrecognized;
1417 		if (0 == (u8) w_value) {
1418 			value = 0;
1419 			dev->current_config = 0;
1420 			usb_gadget_vbus_draw(gadget, 8 /* mA */ );
1421 			// user mode expected to disable endpoints
1422 		} else {
1423 			u8	config, power;
1424 
1425 			if (gadget_is_dualspeed(gadget)
1426 					&& gadget->speed == USB_SPEED_HIGH) {
1427 				config = dev->hs_config->bConfigurationValue;
1428 				power = dev->hs_config->bMaxPower;
1429 			} else {
1430 				config = dev->config->bConfigurationValue;
1431 				power = dev->config->bMaxPower;
1432 			}
1433 
1434 			if (config == (u8) w_value) {
1435 				value = 0;
1436 				dev->current_config = config;
1437 				usb_gadget_vbus_draw(gadget, 2 * power);
1438 			}
1439 		}
1440 
1441 		/* report SET_CONFIGURATION like any other control request,
1442 		 * except that usermode may not stall this.  the next
1443 		 * request mustn't be allowed start until this finishes:
1444 		 * endpoints and threads set up, etc.
1445 		 *
1446 		 * NOTE:  older PXA hardware (before PXA 255: without UDCCFR)
1447 		 * has bad/racey automagic that prevents synchronizing here.
1448 		 * even kernel mode drivers often miss them.
1449 		 */
1450 		if (value == 0) {
1451 			INFO (dev, "configuration #%d\n", dev->current_config);
1452 			usb_gadget_set_state(gadget, USB_STATE_CONFIGURED);
1453 			if (dev->usermode_setup) {
1454 				dev->setup_can_stall = 0;
1455 				goto delegate;
1456 			}
1457 		}
1458 		break;
1459 
1460 #ifndef	CONFIG_USB_PXA25X
1461 	/* PXA automagically handles this request too */
1462 	case USB_REQ_GET_CONFIGURATION:
1463 		if (ctrl->bRequestType != 0x80)
1464 			goto unrecognized;
1465 		*(u8 *)req->buf = dev->current_config;
1466 		value = min (w_length, (u16) 1);
1467 		break;
1468 #endif
1469 
1470 	default:
1471 unrecognized:
1472 		VDEBUG (dev, "%s req%02x.%02x v%04x i%04x l%d\n",
1473 			dev->usermode_setup ? "delegate" : "fail",
1474 			ctrl->bRequestType, ctrl->bRequest,
1475 			w_value, le16_to_cpu(ctrl->wIndex), w_length);
1476 
1477 		/* if there's an ep0 reader, don't stall */
1478 		if (dev->usermode_setup) {
1479 			dev->setup_can_stall = 1;
1480 delegate:
1481 			dev->setup_in = (ctrl->bRequestType & USB_DIR_IN)
1482 						? 1 : 0;
1483 			dev->setup_wLength = w_length;
1484 			dev->setup_out_ready = 0;
1485 			dev->setup_out_error = 0;
1486 
1487 			/* read DATA stage for OUT right away */
1488 			if (unlikely (!dev->setup_in && w_length)) {
1489 				value = setup_req (gadget->ep0, dev->req,
1490 							w_length);
1491 				if (value < 0)
1492 					break;
1493 
1494 				++dev->udc_usage;
1495 				spin_unlock (&dev->lock);
1496 				value = usb_ep_queue (gadget->ep0, dev->req,
1497 							GFP_KERNEL);
1498 				spin_lock (&dev->lock);
1499 				--dev->udc_usage;
1500 				if (value < 0) {
1501 					clean_req (gadget->ep0, dev->req);
1502 					break;
1503 				}
1504 
1505 				/* we can't currently stall these */
1506 				dev->setup_can_stall = 0;
1507 			}
1508 
1509 			/* state changes when reader collects event */
1510 			event = next_event (dev, GADGETFS_SETUP);
1511 			event->u.setup = *ctrl;
1512 			ep0_readable (dev);
1513 			spin_unlock (&dev->lock);
1514 			return 0;
1515 		}
1516 	}
1517 
1518 	/* proceed with data transfer and status phases? */
1519 	if (value >= 0 && dev->state != STATE_DEV_SETUP) {
1520 		req->length = value;
1521 		req->zero = value < w_length;
1522 
1523 		++dev->udc_usage;
1524 		spin_unlock (&dev->lock);
1525 		value = usb_ep_queue (gadget->ep0, req, GFP_KERNEL);
1526 		spin_lock(&dev->lock);
1527 		--dev->udc_usage;
1528 		spin_unlock(&dev->lock);
1529 		if (value < 0) {
1530 			DBG (dev, "ep_queue --> %d\n", value);
1531 			req->status = 0;
1532 		}
1533 		return value;
1534 	}
1535 
1536 	/* device stalls when value < 0 */
1537 	spin_unlock (&dev->lock);
1538 	return value;
1539 }
1540 
destroy_ep_files(struct dev_data * dev)1541 static void destroy_ep_files (struct dev_data *dev)
1542 {
1543 	DBG (dev, "%s %d\n", __func__, dev->state);
1544 
1545 	/* dev->state must prevent interference */
1546 	spin_lock_irq (&dev->lock);
1547 	while (!list_empty(&dev->epfiles)) {
1548 		struct ep_data	*ep;
1549 		struct inode	*parent;
1550 		struct dentry	*dentry;
1551 
1552 		/* break link to FS */
1553 		ep = list_first_entry (&dev->epfiles, struct ep_data, epfiles);
1554 		list_del_init (&ep->epfiles);
1555 		spin_unlock_irq (&dev->lock);
1556 
1557 		dentry = ep->dentry;
1558 		ep->dentry = NULL;
1559 		parent = d_inode(dentry->d_parent);
1560 
1561 		/* break link to controller */
1562 		mutex_lock(&ep->lock);
1563 		if (ep->state == STATE_EP_ENABLED)
1564 			(void) usb_ep_disable (ep->ep);
1565 		ep->state = STATE_EP_UNBOUND;
1566 		usb_ep_free_request (ep->ep, ep->req);
1567 		ep->ep = NULL;
1568 		mutex_unlock(&ep->lock);
1569 
1570 		wake_up (&ep->wait);
1571 		put_ep (ep);
1572 
1573 		/* break link to dcache */
1574 		inode_lock(parent);
1575 		d_delete (dentry);
1576 		dput (dentry);
1577 		inode_unlock(parent);
1578 
1579 		spin_lock_irq (&dev->lock);
1580 	}
1581 	spin_unlock_irq (&dev->lock);
1582 }
1583 
1584 
1585 static struct dentry *
1586 gadgetfs_create_file (struct super_block *sb, char const *name,
1587 		void *data, const struct file_operations *fops);
1588 
activate_ep_files(struct dev_data * dev)1589 static int activate_ep_files (struct dev_data *dev)
1590 {
1591 	struct usb_ep	*ep;
1592 	struct ep_data	*data;
1593 
1594 	gadget_for_each_ep (ep, dev->gadget) {
1595 
1596 		data = kzalloc(sizeof(*data), GFP_KERNEL);
1597 		if (!data)
1598 			goto enomem0;
1599 		data->state = STATE_EP_DISABLED;
1600 		mutex_init(&data->lock);
1601 		init_waitqueue_head (&data->wait);
1602 
1603 		strncpy (data->name, ep->name, sizeof (data->name) - 1);
1604 		refcount_set (&data->count, 1);
1605 		data->dev = dev;
1606 		get_dev (dev);
1607 
1608 		data->ep = ep;
1609 		ep->driver_data = data;
1610 
1611 		data->req = usb_ep_alloc_request (ep, GFP_KERNEL);
1612 		if (!data->req)
1613 			goto enomem1;
1614 
1615 		data->dentry = gadgetfs_create_file (dev->sb, data->name,
1616 				data, &ep_io_operations);
1617 		if (!data->dentry)
1618 			goto enomem2;
1619 		list_add_tail (&data->epfiles, &dev->epfiles);
1620 	}
1621 	return 0;
1622 
1623 enomem2:
1624 	usb_ep_free_request (ep, data->req);
1625 enomem1:
1626 	put_dev (dev);
1627 	kfree (data);
1628 enomem0:
1629 	DBG (dev, "%s enomem\n", __func__);
1630 	destroy_ep_files (dev);
1631 	return -ENOMEM;
1632 }
1633 
1634 static void
gadgetfs_unbind(struct usb_gadget * gadget)1635 gadgetfs_unbind (struct usb_gadget *gadget)
1636 {
1637 	struct dev_data		*dev = get_gadget_data (gadget);
1638 
1639 	DBG (dev, "%s\n", __func__);
1640 
1641 	spin_lock_irq (&dev->lock);
1642 	dev->state = STATE_DEV_UNBOUND;
1643 	while (dev->udc_usage > 0) {
1644 		spin_unlock_irq(&dev->lock);
1645 		usleep_range(1000, 2000);
1646 		spin_lock_irq(&dev->lock);
1647 	}
1648 	spin_unlock_irq (&dev->lock);
1649 
1650 	destroy_ep_files (dev);
1651 	gadget->ep0->driver_data = NULL;
1652 	set_gadget_data (gadget, NULL);
1653 
1654 	/* we've already been disconnected ... no i/o is active */
1655 	if (dev->req)
1656 		usb_ep_free_request (gadget->ep0, dev->req);
1657 	DBG (dev, "%s done\n", __func__);
1658 	put_dev (dev);
1659 }
1660 
1661 static struct dev_data		*the_device;
1662 
gadgetfs_bind(struct usb_gadget * gadget,struct usb_gadget_driver * driver)1663 static int gadgetfs_bind(struct usb_gadget *gadget,
1664 		struct usb_gadget_driver *driver)
1665 {
1666 	struct dev_data		*dev = the_device;
1667 
1668 	if (!dev)
1669 		return -ESRCH;
1670 	if (0 != strcmp (CHIP, gadget->name)) {
1671 		pr_err("%s expected %s controller not %s\n",
1672 			shortname, CHIP, gadget->name);
1673 		return -ENODEV;
1674 	}
1675 
1676 	set_gadget_data (gadget, dev);
1677 	dev->gadget = gadget;
1678 	gadget->ep0->driver_data = dev;
1679 
1680 	/* preallocate control response and buffer */
1681 	dev->req = usb_ep_alloc_request (gadget->ep0, GFP_KERNEL);
1682 	if (!dev->req)
1683 		goto enomem;
1684 	dev->req->context = NULL;
1685 	dev->req->complete = epio_complete;
1686 
1687 	if (activate_ep_files (dev) < 0)
1688 		goto enomem;
1689 
1690 	INFO (dev, "bound to %s driver\n", gadget->name);
1691 	spin_lock_irq(&dev->lock);
1692 	dev->state = STATE_DEV_UNCONNECTED;
1693 	spin_unlock_irq(&dev->lock);
1694 	get_dev (dev);
1695 	return 0;
1696 
1697 enomem:
1698 	gadgetfs_unbind (gadget);
1699 	return -ENOMEM;
1700 }
1701 
1702 static void
gadgetfs_disconnect(struct usb_gadget * gadget)1703 gadgetfs_disconnect (struct usb_gadget *gadget)
1704 {
1705 	struct dev_data		*dev = get_gadget_data (gadget);
1706 	unsigned long		flags;
1707 
1708 	spin_lock_irqsave (&dev->lock, flags);
1709 	if (dev->state == STATE_DEV_UNCONNECTED)
1710 		goto exit;
1711 	dev->state = STATE_DEV_UNCONNECTED;
1712 
1713 	INFO (dev, "disconnected\n");
1714 	next_event (dev, GADGETFS_DISCONNECT);
1715 	ep0_readable (dev);
1716 exit:
1717 	spin_unlock_irqrestore (&dev->lock, flags);
1718 }
1719 
1720 static void
gadgetfs_suspend(struct usb_gadget * gadget)1721 gadgetfs_suspend (struct usb_gadget *gadget)
1722 {
1723 	struct dev_data		*dev = get_gadget_data (gadget);
1724 	unsigned long		flags;
1725 
1726 	INFO (dev, "suspended from state %d\n", dev->state);
1727 	spin_lock_irqsave(&dev->lock, flags);
1728 	switch (dev->state) {
1729 	case STATE_DEV_SETUP:		// VERY odd... host died??
1730 	case STATE_DEV_CONNECTED:
1731 	case STATE_DEV_UNCONNECTED:
1732 		next_event (dev, GADGETFS_SUSPEND);
1733 		ep0_readable (dev);
1734 		fallthrough;
1735 	default:
1736 		break;
1737 	}
1738 	spin_unlock_irqrestore(&dev->lock, flags);
1739 }
1740 
1741 static struct usb_gadget_driver gadgetfs_driver = {
1742 	.function	= (char *) driver_desc,
1743 	.bind		= gadgetfs_bind,
1744 	.unbind		= gadgetfs_unbind,
1745 	.setup		= gadgetfs_setup,
1746 	.reset		= gadgetfs_disconnect,
1747 	.disconnect	= gadgetfs_disconnect,
1748 	.suspend	= gadgetfs_suspend,
1749 
1750 	.driver	= {
1751 		.name		= shortname,
1752 	},
1753 };
1754 
1755 /*----------------------------------------------------------------------*/
1756 /* DEVICE INITIALIZATION
1757  *
1758  *     fd = open ("/dev/gadget/$CHIP", O_RDWR)
1759  *     status = write (fd, descriptors, sizeof descriptors)
1760  *
1761  * That write establishes the device configuration, so the kernel can
1762  * bind to the controller ... guaranteeing it can handle enumeration
1763  * at all necessary speeds.  Descriptor order is:
1764  *
1765  * . message tag (u32, host order) ... for now, must be zero; it
1766  *	would change to support features like multi-config devices
1767  * . full/low speed config ... all wTotalLength bytes (with interface,
1768  *	class, altsetting, endpoint, and other descriptors)
1769  * . high speed config ... all descriptors, for high speed operation;
1770  *	this one's optional except for high-speed hardware
1771  * . device descriptor
1772  *
1773  * Endpoints are not yet enabled. Drivers must wait until device
1774  * configuration and interface altsetting changes create
1775  * the need to configure (or unconfigure) them.
1776  *
1777  * After initialization, the device stays active for as long as that
1778  * $CHIP file is open.  Events must then be read from that descriptor,
1779  * such as configuration notifications.
1780  */
1781 
is_valid_config(struct usb_config_descriptor * config,unsigned int total)1782 static int is_valid_config(struct usb_config_descriptor *config,
1783 		unsigned int total)
1784 {
1785 	return config->bDescriptorType == USB_DT_CONFIG
1786 		&& config->bLength == USB_DT_CONFIG_SIZE
1787 		&& total >= USB_DT_CONFIG_SIZE
1788 		&& config->bConfigurationValue != 0
1789 		&& (config->bmAttributes & USB_CONFIG_ATT_ONE) != 0
1790 		&& (config->bmAttributes & USB_CONFIG_ATT_WAKEUP) == 0;
1791 	/* FIXME if gadget->is_otg, _must_ include an otg descriptor */
1792 	/* FIXME check lengths: walk to end */
1793 }
1794 
1795 static ssize_t
dev_config(struct file * fd,const char __user * buf,size_t len,loff_t * ptr)1796 dev_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
1797 {
1798 	struct dev_data		*dev = fd->private_data;
1799 	ssize_t			value, length = len;
1800 	unsigned		total;
1801 	u32			tag;
1802 	char			*kbuf;
1803 
1804 	spin_lock_irq(&dev->lock);
1805 	if (dev->state > STATE_DEV_OPENED) {
1806 		value = ep0_write(fd, buf, len, ptr);
1807 		spin_unlock_irq(&dev->lock);
1808 		return value;
1809 	}
1810 	spin_unlock_irq(&dev->lock);
1811 
1812 	if ((len < (USB_DT_CONFIG_SIZE + USB_DT_DEVICE_SIZE + 4)) ||
1813 	    (len > PAGE_SIZE * 4))
1814 		return -EINVAL;
1815 
1816 	/* we might need to change message format someday */
1817 	if (copy_from_user (&tag, buf, 4))
1818 		return -EFAULT;
1819 	if (tag != 0)
1820 		return -EINVAL;
1821 	buf += 4;
1822 	length -= 4;
1823 
1824 	kbuf = memdup_user(buf, length);
1825 	if (IS_ERR(kbuf))
1826 		return PTR_ERR(kbuf);
1827 
1828 	spin_lock_irq (&dev->lock);
1829 	value = -EINVAL;
1830 	if (dev->buf) {
1831 		spin_unlock_irq(&dev->lock);
1832 		kfree(kbuf);
1833 		return value;
1834 	}
1835 	dev->buf = kbuf;
1836 
1837 	/* full or low speed config */
1838 	dev->config = (void *) kbuf;
1839 	total = le16_to_cpu(dev->config->wTotalLength);
1840 	if (!is_valid_config(dev->config, total) ||
1841 			total > length - USB_DT_DEVICE_SIZE)
1842 		goto fail;
1843 	kbuf += total;
1844 	length -= total;
1845 
1846 	/* optional high speed config */
1847 	if (kbuf [1] == USB_DT_CONFIG) {
1848 		dev->hs_config = (void *) kbuf;
1849 		total = le16_to_cpu(dev->hs_config->wTotalLength);
1850 		if (!is_valid_config(dev->hs_config, total) ||
1851 				total > length - USB_DT_DEVICE_SIZE)
1852 			goto fail;
1853 		kbuf += total;
1854 		length -= total;
1855 	} else {
1856 		dev->hs_config = NULL;
1857 	}
1858 
1859 	/* could support multiple configs, using another encoding! */
1860 
1861 	/* device descriptor (tweaked for paranoia) */
1862 	if (length != USB_DT_DEVICE_SIZE)
1863 		goto fail;
1864 	dev->dev = (void *)kbuf;
1865 	if (dev->dev->bLength != USB_DT_DEVICE_SIZE
1866 			|| dev->dev->bDescriptorType != USB_DT_DEVICE
1867 			|| dev->dev->bNumConfigurations != 1)
1868 		goto fail;
1869 	dev->dev->bcdUSB = cpu_to_le16 (0x0200);
1870 
1871 	/* triggers gadgetfs_bind(); then we can enumerate. */
1872 	spin_unlock_irq (&dev->lock);
1873 	if (dev->hs_config)
1874 		gadgetfs_driver.max_speed = USB_SPEED_HIGH;
1875 	else
1876 		gadgetfs_driver.max_speed = USB_SPEED_FULL;
1877 
1878 	value = usb_gadget_register_driver(&gadgetfs_driver);
1879 	if (value != 0) {
1880 		spin_lock_irq(&dev->lock);
1881 		goto fail;
1882 	} else {
1883 		/* at this point "good" hardware has for the first time
1884 		 * let the USB the host see us.  alternatively, if users
1885 		 * unplug/replug that will clear all the error state.
1886 		 *
1887 		 * note:  everything running before here was guaranteed
1888 		 * to choke driver model style diagnostics.  from here
1889 		 * on, they can work ... except in cleanup paths that
1890 		 * kick in after the ep0 descriptor is closed.
1891 		 */
1892 		value = len;
1893 		dev->gadget_registered = true;
1894 	}
1895 	return value;
1896 
1897 fail:
1898 	dev->config = NULL;
1899 	dev->hs_config = NULL;
1900 	dev->dev = NULL;
1901 	spin_unlock_irq (&dev->lock);
1902 	pr_debug ("%s: %s fail %zd, %p\n", shortname, __func__, value, dev);
1903 	kfree (dev->buf);
1904 	dev->buf = NULL;
1905 	return value;
1906 }
1907 
1908 static int
gadget_dev_open(struct inode * inode,struct file * fd)1909 gadget_dev_open (struct inode *inode, struct file *fd)
1910 {
1911 	struct dev_data		*dev = inode->i_private;
1912 	int			value = -EBUSY;
1913 
1914 	spin_lock_irq(&dev->lock);
1915 	if (dev->state == STATE_DEV_DISABLED) {
1916 		dev->ev_next = 0;
1917 		dev->state = STATE_DEV_OPENED;
1918 		fd->private_data = dev;
1919 		get_dev (dev);
1920 		value = 0;
1921 	}
1922 	spin_unlock_irq(&dev->lock);
1923 	return value;
1924 }
1925 
1926 static const struct file_operations ep0_operations = {
1927 	.llseek =	no_llseek,
1928 
1929 	.open =		gadget_dev_open,
1930 	.read =		ep0_read,
1931 	.write =	dev_config,
1932 	.fasync =	ep0_fasync,
1933 	.poll =		ep0_poll,
1934 	.unlocked_ioctl = gadget_dev_ioctl,
1935 	.release =	dev_release,
1936 };
1937 
1938 /*----------------------------------------------------------------------*/
1939 
1940 /* FILESYSTEM AND SUPERBLOCK OPERATIONS
1941  *
1942  * Mounting the filesystem creates a controller file, used first for
1943  * device configuration then later for event monitoring.
1944  */
1945 
1946 
1947 /* FIXME PAM etc could set this security policy without mount options
1948  * if epfiles inherited ownership and permissons from ep0 ...
1949  */
1950 
1951 static unsigned default_uid;
1952 static unsigned default_gid;
1953 static unsigned default_perm = S_IRUSR | S_IWUSR;
1954 
1955 module_param (default_uid, uint, 0644);
1956 module_param (default_gid, uint, 0644);
1957 module_param (default_perm, uint, 0644);
1958 
1959 
1960 static struct inode *
gadgetfs_make_inode(struct super_block * sb,void * data,const struct file_operations * fops,int mode)1961 gadgetfs_make_inode (struct super_block *sb,
1962 		void *data, const struct file_operations *fops,
1963 		int mode)
1964 {
1965 	struct inode *inode = new_inode (sb);
1966 
1967 	if (inode) {
1968 		inode->i_ino = get_next_ino();
1969 		inode->i_mode = mode;
1970 		inode->i_uid = make_kuid(&init_user_ns, default_uid);
1971 		inode->i_gid = make_kgid(&init_user_ns, default_gid);
1972 		inode->i_atime = inode->i_mtime = inode_set_ctime_current(inode);
1973 		inode->i_private = data;
1974 		inode->i_fop = fops;
1975 	}
1976 	return inode;
1977 }
1978 
1979 /* creates in fs root directory, so non-renamable and non-linkable.
1980  * so inode and dentry are paired, until device reconfig.
1981  */
1982 static struct dentry *
gadgetfs_create_file(struct super_block * sb,char const * name,void * data,const struct file_operations * fops)1983 gadgetfs_create_file (struct super_block *sb, char const *name,
1984 		void *data, const struct file_operations *fops)
1985 {
1986 	struct dentry	*dentry;
1987 	struct inode	*inode;
1988 
1989 	dentry = d_alloc_name(sb->s_root, name);
1990 	if (!dentry)
1991 		return NULL;
1992 
1993 	inode = gadgetfs_make_inode (sb, data, fops,
1994 			S_IFREG | (default_perm & S_IRWXUGO));
1995 	if (!inode) {
1996 		dput(dentry);
1997 		return NULL;
1998 	}
1999 	d_add (dentry, inode);
2000 	return dentry;
2001 }
2002 
2003 static const struct super_operations gadget_fs_operations = {
2004 	.statfs =	simple_statfs,
2005 	.drop_inode =	generic_delete_inode,
2006 };
2007 
2008 static int
gadgetfs_fill_super(struct super_block * sb,struct fs_context * fc)2009 gadgetfs_fill_super (struct super_block *sb, struct fs_context *fc)
2010 {
2011 	struct inode	*inode;
2012 	struct dev_data	*dev;
2013 	int		rc;
2014 
2015 	mutex_lock(&sb_mutex);
2016 
2017 	if (the_device) {
2018 		rc = -ESRCH;
2019 		goto Done;
2020 	}
2021 
2022 	CHIP = usb_get_gadget_udc_name();
2023 	if (!CHIP) {
2024 		rc = -ENODEV;
2025 		goto Done;
2026 	}
2027 
2028 	/* superblock */
2029 	sb->s_blocksize = PAGE_SIZE;
2030 	sb->s_blocksize_bits = PAGE_SHIFT;
2031 	sb->s_magic = GADGETFS_MAGIC;
2032 	sb->s_op = &gadget_fs_operations;
2033 	sb->s_time_gran = 1;
2034 
2035 	/* root inode */
2036 	inode = gadgetfs_make_inode (sb,
2037 			NULL, &simple_dir_operations,
2038 			S_IFDIR | S_IRUGO | S_IXUGO);
2039 	if (!inode)
2040 		goto Enomem;
2041 	inode->i_op = &simple_dir_inode_operations;
2042 	if (!(sb->s_root = d_make_root (inode)))
2043 		goto Enomem;
2044 
2045 	/* the ep0 file is named after the controller we expect;
2046 	 * user mode code can use it for sanity checks, like we do.
2047 	 */
2048 	dev = dev_new ();
2049 	if (!dev)
2050 		goto Enomem;
2051 
2052 	dev->sb = sb;
2053 	dev->dentry = gadgetfs_create_file(sb, CHIP, dev, &ep0_operations);
2054 	if (!dev->dentry) {
2055 		put_dev(dev);
2056 		goto Enomem;
2057 	}
2058 
2059 	/* other endpoint files are available after hardware setup,
2060 	 * from binding to a controller.
2061 	 */
2062 	the_device = dev;
2063 	rc = 0;
2064 	goto Done;
2065 
2066  Enomem:
2067 	kfree(CHIP);
2068 	CHIP = NULL;
2069 	rc = -ENOMEM;
2070 
2071  Done:
2072 	mutex_unlock(&sb_mutex);
2073 	return rc;
2074 }
2075 
2076 /* "mount -t gadgetfs path /dev/gadget" ends up here */
gadgetfs_get_tree(struct fs_context * fc)2077 static int gadgetfs_get_tree(struct fs_context *fc)
2078 {
2079 	return get_tree_single(fc, gadgetfs_fill_super);
2080 }
2081 
2082 static const struct fs_context_operations gadgetfs_context_ops = {
2083 	.get_tree	= gadgetfs_get_tree,
2084 };
2085 
gadgetfs_init_fs_context(struct fs_context * fc)2086 static int gadgetfs_init_fs_context(struct fs_context *fc)
2087 {
2088 	fc->ops = &gadgetfs_context_ops;
2089 	return 0;
2090 }
2091 
2092 static void
gadgetfs_kill_sb(struct super_block * sb)2093 gadgetfs_kill_sb (struct super_block *sb)
2094 {
2095 	mutex_lock(&sb_mutex);
2096 	kill_litter_super (sb);
2097 	if (the_device) {
2098 		put_dev (the_device);
2099 		the_device = NULL;
2100 	}
2101 	kfree(CHIP);
2102 	CHIP = NULL;
2103 	mutex_unlock(&sb_mutex);
2104 }
2105 
2106 /*----------------------------------------------------------------------*/
2107 
2108 static struct file_system_type gadgetfs_type = {
2109 	.owner		= THIS_MODULE,
2110 	.name		= shortname,
2111 	.init_fs_context = gadgetfs_init_fs_context,
2112 	.kill_sb	= gadgetfs_kill_sb,
2113 };
2114 MODULE_ALIAS_FS("gadgetfs");
2115 
2116 /*----------------------------------------------------------------------*/
2117 
gadgetfs_init(void)2118 static int __init gadgetfs_init (void)
2119 {
2120 	int status;
2121 
2122 	status = register_filesystem (&gadgetfs_type);
2123 	if (status == 0)
2124 		pr_info ("%s: %s, version " DRIVER_VERSION "\n",
2125 			shortname, driver_desc);
2126 	return status;
2127 }
2128 module_init (gadgetfs_init);
2129 
gadgetfs_cleanup(void)2130 static void __exit gadgetfs_cleanup (void)
2131 {
2132 	pr_debug ("unregister %s\n", shortname);
2133 	unregister_filesystem (&gadgetfs_type);
2134 }
2135 module_exit (gadgetfs_cleanup);
2136 
2137